Vibratory energy generators

ABSTRACT

Energy emitted in a rearward direction from vibratory energy transducers is conveyed from the rear end of a transducer to another by coupling members of equal length joining similar portions of the rear ends of the transducers. In the preferred embodiment the coupling members are of steel rods and are stranded in the form of steel rope without a central crown rod.

F I, 1? s I /v M 3 1, Q m 3 .3 .2 a 3 A ms. afivemell a van-UV- vwuvvu lutbllt I [H] [72] Inventor Leslie Tremaine Russell [50] Field of Search3 10/26, 8.1, Canada 8.2, 8.3, 8.7; 340/10, 11 [2 1] Appl. No. 11,614221 Filed Feb. 16, 1970 Continuation-impart of Ser. No. 797,492, UNITEDSTATES PATENTS 7,1969 3,225,326 12/1965 Massa 340/11X z e g y 12,753,543 7/1956 Rymes 310/26X e e men's and Devehpme'" PrimaryExaminer-Milton o. Hirshfield Ottawa Ontario Canada AssistantExaminer-B. A. Reynolds A BSTRACT: Energy emitted in a rea rivzirddirection from [54] VIBRATORY ENERGY GENERATORS vibratory energytransducers is conveyed from the rear end of 4 Claims, 1 Drawing g etrensducer to another by coupling members of equal length 52 s I oiningsimilar portions of the rear ends of the transducers. U. C 310/83, Inthe preferred embodirnent the coupling members are of [51] Int Cl R013 1steel rcl ds and are stranded in the form of steel rope without a vcentra crown rod.

VIBRATORY ENERGY GENERATORS This invention relates to vibratory energygenerators.

With vibratory energy generators in the formof magnetostrictive andpiezoelectric transducers, vibratory energy is propagated in a rearwarddirection as well as in the forward direction in which the energy isrequired. Usually this rearward-propagated energy is dissipated in amass of metal or other material and so is not usefully employed. Infact, in, for example, sonic transducers used for echo sounding thisrearward-propagated energy can be a nuisance if a large proportion of itis not dissipated because it may result in spurious echos.

lt is an object of the present invention to usefully employ rearwardlypropagated energy in a vibratory energy transducer.

According to the present invention there is provided a vibratory energygenerator, comprising a plurality of similar vibratory energy-producingtransducer elements disposed side by side with each said element havinga forward vibratory energy-propagating surface facing thegenerator-transmitting direction, and a rearward vibratoryenergy-propagating surface, a plurality of vibrating energy-conveyingcoupling members joining said rearward surfaces to another, wherebyrearwardly propagated energy from each said element will be transferredto another said element to be emitted from the latter element from theforward surface thereof in the direction and in phase with theforward-propagated energy from that element.

In the accompany drawing which illustrates, by way of example, anembodiment of the present invention there is shown two transducingelements of a vibratory energy generator.

In the drawing there is shown two vibratory energy-producing transducingelements 1 and 2 of a vibratory energy generator mounted in a nodalplate 3 and secured at their forward vibratory energy-propagatingsurfaces by heads 9 to a diaphragm 4. The elements 1 and 2 are providedwith tails 5 and 6 respectively which are joined by a plurality ofvibratory energy conveying coupling members generally designated 7. Thecoupling members 7 are substantially rigid steel rods stranded togetherin a helical fashion without a center crown rod. Each rod is stranded tohave one complete helical turn so that it connects corresponding areasof each tail 5 and 6 together. Thus, a rod 8 joins a right-hand portionof tail 5 to a corresponding right-hand portion of tail 6. The couplingmembers 7 are equal in length and the inner layers of rods are eachgiven a more acute helix angle. the closer they are to the center forthis purpose. The coupling members 7 may be touching but aresufficiently loosely wound together to allow relative movements betweenthem. Being of a substantially rigid material such as steel the rods arecircular in cross section. If they were of a less rigid material such ascopper the cross section would then have to be larger in diameter orrectangular to impart rigidity to them. The rigidity would be impartedby the longer sides of the rectangle extending from left to right in thedrawing where the coupling members 7 are joined to the tails 5 and 6.

in operation the elements 1 and 2, which may be magnetostrictive,piezoelectric or any other electromechanical elements, are energized toimpart vibratory energy by their forward vibratory energy-propagatingsurfaces to the diaphragm Each rearward vibratory energy-propagatingsurface propagates vibratory energy in a rearward direction which is atthe same frequency and in phase with the energy propagated from theforward vibrating energy-propagating surface. The coupling memberlengths are NA where N is an integer and A is the wave length of thevibratory energy being generated so that a substantial proportion of therearwardly propagated vibratory energy is conveyed from each rearwardsurface to the other. Thus rearwardly propagated vibratory energy fromeach element 1 and 2 is transferred from one element to another to beemitted from the latter element from the forward surface thereof in thedirectionand in phase with the forward-propagated energy from thatelement and hence substantially eliminating the rearward propagation ofvibratory energy therefrom.

It is essential that the coupling members 7 cover substantially thewhole of the rearward surfaces of the elements 1 and 2. To this end itmay be desirable to thicken the end portions of coupling members 7 inthe shape of an elephants foot.

lt is also essential that the coupling members be connected, by forexample an adhesive such as epoxy resin, welding or brazing, at rightangles to the rearward surface with respect to their longitudinal axisat the joint. Furthermore sharp comers on the coupling members should beavoided as reflected vibrations will be produced at sharp comers.

The lengths of the tails 5 and 6 may have to be adjusted to suit thefrequency of the vibrations, in combination with the coupling members.

The coupling members may be of any material which will convey thevibratory energy provided it is sufficiently rigid not to flex, steel isan ideal material but nickel, copper or other materials may be used. Ifdesired the coupling members may be coated with a material such as whichwill act as a lubricant and assist relative movements between thecoupling members The coupling members 7 may be helically wound with onecomplete turn or in multiples of complete turns so that correspondingareas of each element 1 and 2 joined to one another.

Whilst two elements 1 and 2 are shown joined to one another, any numberof elements may be coupled in pairs in this manner. Where three elementsare used they may be disposed as at the points of a triangle so that onehalf of each element can be coupled to a Corresponding half of anotherelement. Thus all of the elements are coupled to one another in thisembodiment.

There will inevitably be some reflections at the joints between thecoupling members 7 and the tails 5 and 6. Furthermore as vibratoryenergy is travelling in both directions along the coupling members 7there will be some cancelling out efiect. However, these losses will besmall.

It will be appreciated that the underneath layers of coupling members 7may be wound in the same or opposite direction to that of the outerlayer. The coupling members need not be wound together but may besplayed in order not to foul one another, however, it is preferred thatthey are wound together as this is a more compact arrangement.

The vibratory energy generators having coupled transducing elements maybe used in many applications such as, for example, sonar detection,welding, machining, cleaning, piling and agitation, cavitation orboiling.

lclaim:

l. A vibratory energy generator, comprising a plurality of similar,vibratory energy-producing transducer elements disposed side by side,with each said element having a forward vibratory energy-propagatingsurface facing the generatortransmitting direction and a rearwardvibratory energypropagating surface, a plurality of substantially rigidvibrating energy-conveying coupling members each NA in length where N isan integer and A is the wave length of the vibratory energy to bepropagated, said coupling members joining substantially the whole ofsaid rearward surfaces to convey rearwardly propagated energy from onesaid rearward surface to another, whereby rearwardly propagated energyfrom each said element will be transferred to another said element to beemitted from the latter element from the forward surface thereof in thedirection and in phase with the forward-propagated energy from thatelement.

2. A generator as claimed in claim 1, wherein said coupling memberscomprise for each said element a plurality of substantially rigid metalloops, all of said loops forming vibratory energy-conveying paths ofequal length with substantially no vibratory energy-reflecting surfacestherealong.

3. A generator as claimed in claim 2. wherein said coupling members arehelically wound together. H

4. A generator as claimed in claim I, wherein tail members areinterposed between the said coupling members and the said elements.

1. A vibratory energy generator, comprising a plurality of similar,vibratory energy-producing transducer elements disposed side by side,with each said element having a forward vibratory energy-propagatingsurface facing the generator-transmitting direction and a rearwardvibratory energy-propagating surface, a plurality of substantially rigidvibrating energy-conveying coupling members each N lambda in lengthwhere N is an integer and lambda is the wave length of the vibratoryenergy to be propagated, said coupling members joining substantially thewhole of said rearward surfaces to convey rearwardly propagated energyfrom one said rearward surface to another, whereby rearwardly propagatedenergy from each said element will be transferred to another saidelement to be emitted from the latter element from the forward surfacethereof in the direction and in phase with the forward-propagated energyfrom that element.
 2. A generator as claimed in claim 1, wherein saidcoupling members comprise for each said element a plurality ofsubstantially rigid metal loops, all of said loops forming vibratoryenergy-conveying paths of equal length with substantially no vibratoryenergy-reflecting surfaces therealong.
 3. A generator as claimed inclaim 2, wherein said coupling members are helically wound together. 4.A generator as claimed in claim 1, wherein tail members are interposedbetween the said coupling members and the said elements.